Java is a powerful scripting tool, but you may not realize just how powerful. This chapter is a tour of various java-based programs around the web, from immersive online games to monitoring satellites.

Before
you
venture
further
into
Java
programming,
it’s
worthwhile
to learn
more
about
the
language
and
see
what
Java
programmers
are
doing
today.
One
of the
reasons
that
Java
became
popular
so quickly
was
because
it could
be used
to offer
programs
on the
World
Wide
Web.
Though
Java
has
outgrown
its
origins
as a
language
focused
on Web
programs,
you
can
still
find
some
interesting
examples
of how
Java
is used
on the
Web.

During
this
hour,
we’ll
take
a look
at some
sites
that
feature
Java
programs
and
talk
about
the
history
and
development
of the
language.

To
go on
this
vacation,
you
need
a web
browser
that
can
handle
Java
programs.
The
current
versions
of Microsoft
Internet
Explorer,
Mozilla
Firefox,
and
the
Opera
browser
can
run
Java
programs
that
are
found
on web
pages.

Did
you Know?

If
you’re
using a current version of Mozilla
Firefox or Microsoft Internet
Explorer and it isn’t
working with Java programs, check
your setup configuration from
one of the program’s
pull-down menus (Tools, Options
in Firefox or Tools, Internet
Options in Internet Explorer).
Make sure your browser software
has Java enabled in its settings.

Load
your
browser
software
of
choice,
put
on
your
best
batik
shirt,
and
get
ready
to
take
a
vacation.
Because
you
won’t
be
leaving
your
house,
you
won’t
get
a
chance
to
experience
the
simpler
pleasures
of
tourism:
odd
driving
rituals,
exotic
food,
exotic
members
of
the
opposite
sex,
exotic
members
of
the
opposite
sex
with
food,
and
so
on.
But
look
on
the
bright
side:
no
antibacterial
shots,
traveler’s
checks,
or
passports
are
required
either.

The
following
topics
will
be
covered
during
this
hour:

A
definition of the Java language

The
benefits of using Java

Some
examples of Java at work

An
explanation of object-oriented
programming

Sites
of note for Java programmers

First Stop: Sun Microsystems

The Java vacation begins at a place you’ll be visiting regularly, now
that you’re a Java programmer: the website of Sun Microsystems, the
company that developed the Java language. To get there, go to
http://java.sun.com.

A Java program that runs as part of a web page is called an applet.
Applets are placed on pages like other elements of a page—a markup
language called HTML is used to define where the program should be displayed,
how big it is, and what the program does when it runs.

The Java division of Sun Microsystems is responsible for the advancement of
the Java language and the development of related software. As you might expect
of a proud parent, Sun uses Java applets on its site. There’s a glossary
applet that’s a guide to the site, several applets that are free for your
own use, and others.

The sample applets include an animated clock and a shopping cart assistant,
which you can try by visiting the web page at
http://java.sun.com/openstudio.
Java can be a great attention-getter, creating content dynamically that changes
as a page is being viewed in a web browser. Figure
3.1 shows the clock and other
sample applets.

Figure 3.1 Sun’s
official Java website offers several Java programs for use on your own
website.

Sun’s Java site is the place to find the latest released versions of
the Java Development Kit as well as other programmer’s resources. This
site offers announcements about Java-related products, full documentation for
Java, and discussion forums where programmers can help each other as they learn
the language. Sun Microsystems first made Java available for free via this
website in 1995, and it’s still the first place to look for each new
version of the language and Java Development Kit upgrade.

A Brief History of Java

Sun co-founder Bill Joy called Java "the end result of fifteen years of
work to produce a better, more reliable way to write computer programs."
Java’s creation was a little more complicated than that.

Java was developed in 1990 by Sun engineer James Gosling as a language that
would serve as the brains for smart appliances (interactive TVs, omniscient
ovens, SkyNet military satellites with artificial intelligence that enslave
mankind—you get the idea). Gosling was unhappy with the results he was
getting by writing programs with C++, another programming language, so he holed
up in his office and wrote a new language to better suit his needs.

By the Way

Unfortunately, many of us like writing programs with Java so much that we
have no incentive to create our own programming languages. This gives us more
time to hole up in our offices and play MineSweeper instead.

Gosling named his new language Oak after a tree he could see from his office
window. The language was part of Sun’s strategy to make millions when
interactive TV became a multimillion-dollar industry. That still hasn’t
happened today (though TiVo, and ReplayTV are making a game attempt), but
something completely different took place for Gosling’s new language.
Just as Sun was ready to scrap Oak development and scatter its workers to other
parts of the company, the World Wide Web became popular.

In a fortuitous circumstance, many of the qualities that made Gosling’s
language good on its appliance project made it suitable for adaptation to the
Web. Sun developers devised a way for programs to be run safely from web pages
and chose a catchy new name to accompany the language’s new focus:
Java.

Although Java can be used for many other things, the Web provided the
showcase it needed to capture international attention. A programmer who puts a
Java program on a web page makes it instantly accessible to the entire
Web-surfing planet. Because Java was the first technology that could offer this
capability, it became the first computer language to receive star treatment in
the media. When the language rose to prominence in 1996, you had to be in
solitary confinement or a long-term orbital mission to avoid hearing about
Java.

By the Way

You might have heard that Java is an acronym that stands for Just Another
Vague Acronym. You also might have heard that it was named for the
developers’ love of coffee, especially the percolating product from a shop
near Sun’s offices. Actually, the story behind Java’s naming
contains no secret messages or declarations of liquid love. Java was chosen as
the name for the same reason that comedian Jerry Seinfeld likes to say the word
salsa. It sounds cool.

There have been six major releases of the Java language:

Fall 1995: Java 1.0—The original release

Spring 1997: Java 1.1—An upgrade to the language that improved the
way user interfaces are created and handled

Summer 1998: Java 2 version 1.2—A version more than three times as
large as Java 1.0, making the language a worthy competitor to other
general-purpose programming languages